At 77, Doug Erbeck is retired — technically — but you won’t find him sitting in a rocking chair killing time.

When he’s not angling for panfish on Twin Cities-area lakes, which is frequently, or competing in long-distance running races, or gardening, or volunteering with the Fur, Fin & Feather Club in Osseo, the former veterinary pathologist peddles an easy-tie fishing jig he invented and sells.

He calls it the Fisherbeck lure.

“I guarantee you’ll catch more and larger bluegills with the easiest-to-thread jig on the market today,’’ said the gregarious Erbeck, of Crystal.

Fumbling while trying to tie 2-pound-test fishing line onto a small jig one cold winter morning several years ago, Erbeck had a light bulb moment. “Those darn little bitty jigs have such small eyes, they’re hard to thread,’’ he said.

And paint must first be removed from them — a tedious affair. Erbeck figured he could do better.

In 2010, he made a clay model and brainstormed with son-in-law Marty Stone of Arden Hills, an engineer. The result: Fisherbeck Easy Threading Jigs, which have funnels to thread the line through instead of a small eye. He got a patent, found a manufacturer and began making and selling them.

“It’s easier to thread for everybody, but it’s particularly attractive for elderly people, for handicapped people, for kids and for ice fishing, because your hands get cold,’’ he said.

But Erbeck found it difficult getting into the tackle-making business; there’s lots of competition.

“I did the patent all by myself, without any lawyers,’’ he said proudly. “The first lawyer I talked to wanted $15,000 to do it. So I went online. The patent office people actually helped me.’’

He sells the jigs three for $5 on his website (www.fisherbeck.com), at fishing shows and a few bait shops, including Frankies Bait in Chisago City, Capra’s Sporting Goods in Blaine, Harty’s Bait Shop at Medicine Lake and Vados Bait in Spring Lake Park.

Sales have been good, but Erbeck laughs when asked if he’s getting rich.

“It’s coming slow but sure,’’ he said. “I’m not making a lot of money, just enough to put back into the business.’’

He’s adding a second jig, one to target big crappies. “It will be the same as the Fisherbeck, only a different color, white glow-in-the-dark with pink eyes. Hopefully, this will take off.’’

His jigs originally were made in China, but he’s found a manufacturer in Illinois to make the next batch, including the new crappie jigs. All are made of tin instead of lead.

“It’s environmentally friendly,’’ Erbeck said. “And with tin, it sinks a bit slower and the fish will grab it.’’

The orange and black jigs are meant to be especially effective on bluegills, Erbeck’s favorite fish.

“To me, bluegills are the premier eating fish of Minnesota,” he said. “And it’s so much fun.’’

He knows Minnesota is a walleye state. “But I’m completely into bluegills; I catch walleyes accidentally.’’

And crappies.

“I catch a lot of crappies,’’ Erbeck said. “Yesterday I caught twice as many crappies as bluegills.’’

He doesn’t use minnows. “I use a white plastic twister tail, or a couple of waxworms,’’ Erbeck said. Sometimes he jigs or casts his lure, sometimes he uses a bobber and still-fishes.

Regardless, he’s on the water about twice a week, year-round.

“I limit myself to lakes right in the Twin Cities,’’ he said. He figures he’s fished about 40 metro lakes.

“I make one exception: Lake Osakis. That’s my nirvana,’’ Erbeck said. “Just like walleye fishermen go to Mille Lacs, I go to Osakis. I know some spots and I catch some really big bluegills.

Erbeck spent most of his life in Wisconsin. He was born in Superior, grew up near Green Bay and, after becoming a veterinarian, operated two small-animal hospitals and a clinic in the Chippewa Falls-Eau Claire area.

“At age 50, I felt I was getting behind what was happening in medicine, so I went back to school and got a Ph.D. in veterinary pathology, which took me to Kentucky,’’ he said.

Where he got hooked on panfish. “People there were really into crappies, and I started fishing for them and found huge bluegills,’’ Erbeck said.

He moved to Minnesota 12 years ago and did cancer research, then retired three years ago — only to go into the tackle-making business with two partners, son-in-law Stone and daughter Amy.

Erbeck is a member of the Minnesota Distance Runners Association, and ran a half-marathon this spring in 2 hours, 23 minutes. “At my age, I was happy with it,’’ he said. “I think running has helped my health and mental well-being.’’

He also has an understanding partner. “My wife, Faye, has supported my fishing and hunting all 53 years of our marriage,’’ Erbeck said. They have three daughters and nine grandchildren.